Chrysler Repair: 2002 Dodge Stratus A/C Compressor Not Engaging, condenser fans, refrigerant pressure

Question
Good afternoon Kevin,

I have a 2002 Dodge Stratus 2.4L Sedan. The a/c compressor will not engage through normal system means. We just purchased this vehicle about two months ago for my college age son and the a/c has been freezing up after about 20-30 minutes of highway driving. We have done a lot of other very much needed work to the vehicle, and the a/c is the last hurdle to overcome.

We started looking at the a/c this past weekend and discovered a previous owner had jumpered the compressor on in the front fuse box, so that when the key is on it is engaged, running full time. I know this is not good, don't know how long it has been this way, and needs to be remedied ASAP.

When initially discovering the jumper, we immediately assumed either the inside control panel or the pressure switch was bad. Both were replaced with no help. We vacuumed and recharged the system with two cans of R134a (about 22 oz.), no change. When idling the low side stays around 35-40 for a few minutes then goes up to around 65-70. The high side stays around 165-175 with the condenser fans on, goes up to around 200 then they kick on and it drops back down. Outside ambient at time was about 85F.

It should be noted the check engine light is permanently on with no codes in the system (I mention this because it was brought up in a forum somewhere about a/c issues, don't know if it is related).

Other than a loose plug/connector wire or something unusual, do you have any ideas?

Thank you.

Answer
Hi Howard,
I assume that to get the pressure readings of the refrigerant that you by-passed the ac clutch relay (the same way that you found the vehicle after purchase), correct? I say that because I infer that is still the problem: that the compressor won't activate when ac is requested.
Aside from the refrigerant pressure requirements, the clutch will not be activated unless the evaporator temp sensor show that it is not too cold (prevention of freeze-up at the evaporator coils) and of course the clutch relay circuit has to be good.
The clutch relay coil has to have 12v on the pin #62 (inboard-rear most pin in the relay socket, with key in the 'run position') in order to close, and it has to have a connection from pin #60 (in-board-front most pin in the relay socket) to pin 11 of the PCM plug #3 (dark blue/orange wire). I assume that your pcm has four plugs and #3 is the third counting from the inboard-most plug.
The evap temp sensor needs to have working fuses at position 6 in the power distribution box and position 6 in the junction block box (the engine and cabin fuse boxes) so check out both those fuses. Its wiring circuit is a bit complex so let me know if all the above checks out and then I can tell you the wiring for that sensor.
Sorry for the delay in responding but I just found your question in the "pool" to which Kevin had referred it.
Please "rate/nominate" my answer/me (see the PS below).
Thanks,
Roland